So what exactly does the world's most expensive footballer—fresh from a title-winning season in La Liga and a Spanish Super Cup triumph over Barcelona, and with goals falling out of him every time he takes the field—have to be miserable about?

More importantly, what does he want to achieve by telling us he's miserable about it?

"I’m sad," Ronaldo told reporters after Sunday's 3-0 win against Granada, a match in which he scored twice. "When I don’t celebrate goals it’s because I’m not happy. It’s a professional thing. Real Madrid know why I’m not happy."

Madrid might know, but we still don't. It's been 48 hours now, and Ronaldo's misery remains a mystery.

What we do know, from the man itself, is it's not about Andres Iniesta winning UEFA's Player of the Year award ahead of Ronaldo—who came in joint second with Lionel Messi. Not even Ronaldo is quite that vain.

We also know it's not about his relationship with Madrid manager Jose Mourinho. The two Portuguese are said to enjoy a strong bond, and their mutual respect has been clear from the start.

Whatever the reason for his malaise, Ronaldo, as a result of his whimpering, has in the last two days been linked with a transfer to every club on the planet that might somehow have the means to afford him.

If one of those is ready and willing to stump up Ronaldo's reported one billion euros buyout clause ($1.26 billion), then who knows—maybe Madrid would consider cashing in.

Jasper Juinen/Getty Images

It's quite the sensational transfer rumor, but are we really to believe Ronaldo is considering leaving Madrid, the club of his boyhood dreams? Or were his comments on Sunday night simply designed to empower his bargaining position for a more lucrative deal at the Bernabeu?

Why is Ronaldo sad?

Wants more moneyWants to be lovedWants to win thingsSubmit Votevote to see results

Why is Ronaldo sad?

Wants more money

25.9%

Wants to be loved

52.9%

Wants to win things

21.2%

Total votes: 7,261

That's one theory, and it's backed by the notion Ronaldo might feel his haul of 60 goals last season has earned him a bump on the reported £215,000/week salary he takes home at Madrid.

When you consider that that's less than Wayne Rooney picks up at Manchester United, less than Zlatan Ibrahimovic is earning at PSG and—most preposterously of all—less than Samuel Eto'o banks at Anzhi, then maybe Ronaldo has a point.

But his Madrid teammate Alvaro Arbeloa doesn't subscribe to the greed theories, nor the notion Ronaldo is motivated purely by his pursuit of individual glories (Marca, as quoted by Daily Mail):

His ambition has turned him into one of the world's greatest, but the most important thing for him is Real Madrid.

Do not think that winning the Ballon d'Or is his primary concern. We are a family, we have to help him. Don't go thinking that money is the issue.

So if it's not money, what is it?

According to respected Spanish title Marca.com, Ronaldo told Madrid president Florentino Perez he doesn't feel wanted at the club:

Ronaldo is more concerned about respect, affection and recognition as opposed to an improved contract. The player does not feel he has the backing of the club, his teammates or the fans. At least, not the way he believes he deserves.

The article goes on to suggest Ronaldo was upset that he wasn't accompanied by more Madrid representatives at the Best Player award ceremony in Monaco. It also claims he yearns for greater respect from his teammates and would like to be the club's captain—an honor that traditionally goes to Madrid's longest-serving player, currently Iker Casillas.

Marca also reports Ronaldo is desperate for greater approval from Madrid's fans.

Could it really be that Ronaldo is just a footballer who needs to be loved? Has his formidable goal scoring and penchant for "peacocking" made Madrid and their fans forget they have a player whose ego needs to be stroked?

Or are we walking the well-trodden ground of a fabulously rich footballer trying to get richer?